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Colonization pattern of Pasteurella pneumotropica in mice with latent pasteurellosis
K Mikazuki1, T Hirasawa, H Chiba
1Aburahi Laboratories, Shionogi & Co., Ltd., Shiga, Japan.
Abstract:
Colonization pattern of Pasteurella pneumotropica (P. pneumotropica) in mice with latent pasteurellosis was examined with the original selective media, NKBT medium and TGN broth. In the mice of 0 to 15 weeks old, the organism was mainly isolated from the upper respiratory tract, lower intestinal tract, feces and vagina, with the highest isolation rate in the pharyngolarynx. In the pregnant and lactating mice, the organism was isolated from the same sites, but not from the uterus, fetus or mammary gland. In the neonates, the organism was isolated from the respiratory and intestinal tracts within 24hr after birth. The organism was constantly detected in the feces of the 0- to 20-week-old mice, with the highest viable count one week after birth. Through the monitoring of mouse colonies, the pharyngolarynx always showed higher isolation rate than the feces in several mouse strains. These results reveal that the pharyngolarynx is the primary colonization site of P. pneumotropica in mice, and the lower intestinal tract and vagina are also the main sites. Further, frequent isolation of the organism from the feces and vagina, and the results in neonates suggest the mode of the transmission to newborn mice in the colony, i.e., intravaginal infection at the partition, and oro-nasal infection through the maternal feces and saliva.
Insights
Pasteurella pneumotropica primarily colonizes the pharyngolarynx in mice, with significant presence in the intestinal tract and vagina. This study clarifies transmission routes to neonates, crucial for understanding latent pasteurellosis.
Area of Science:
- Microbiology
- Animal Health
- Infectious Diseases
Background:
- Pasteurella pneumotropica (P. pneumotropica) is a common bacterium in laboratory mice, often causing latent infections.
- Understanding its colonization patterns is vital for maintaining healthy mouse colonies and preventing disease transmission.
Purpose of the Study:
- To identify the primary colonization sites of P. pneumotropica in mice with latent pasteurellosis.
- To elucidate the transmission routes of P. pneumotropica to newborn mice within a colony setting.
Main Methods:
- Utilized selective media (NKBT medium and TGN broth) for isolating P. pneumotropica.
- Examined colonization in mice of various ages (0-20 weeks), including pregnant, lactating, and neonate individuals.
- Monitored isolation rates from different body sites (respiratory tract, intestinal tract, feces, vagina, uterus, fetus, mammary gland).
Main Results:
- The pharyngolarynx was identified as the primary colonization site, showing the highest isolation rates.
- P. pneumotropica was also frequently isolated from the lower intestinal tract and vagina.
- In neonates, the organism was detected in respiratory and intestinal tracts within 24 hours of birth, with high fecal counts one week post-birth.
Conclusions:
- The pharyngolarynx serves as the main reservoir for P. pneumotropica in mice.
- The lower intestinal tract and vagina are significant secondary colonization sites.
- Transmission to neonates likely occurs via intravaginal or oro-nasal routes involving maternal contact with feces and saliva.